Mechanical fabric



Patented Mar. 2, 1943 MECHANICAL FABRIC Carlton C. Gordon, Elsmer'e, N. Y.,assignorto Al' j f f ban'y Felt Company, Albany, N. Y., a corporation of New York No Drawing. Application March 18, Serial No. 324,663

*4 Claims. (Cl. 111-101 My invention relates to fabrics which are used in connection with or form parts of machines for the manufacture or treatment of other fabrics and which, in such use,-are usually subjected to both moisture and heat. Papermakers felts and blankets, and palmer' and sanforizing blankets are examples of the class of fabrics to which my invention relates, and are referred to herein as mechanical fabrics. v

In themanufacture of paper, for example, the wet web of fiber is dried by carrying it around steam heated cylinders with the surface of which it is held in contact by a felt belt coextensive therewith.

In the sanforizing process of mechanically shrinking fabrics a felt blanket is used to hold the moist fabric in contact with the surface of a heated cylinder in order to dry it. Similarly, the finishing of silk fabrics on palmer machines involves evaporating moisture from the silk by running it about a heated cylinder with whichit is held in contact by a blanket.

In all these processes, and in similar ones, the felt or blanket employed is a heavy fabric which consists, at least in part, of wool, and

which is subjected to moisture and high temperature for long periods in the manner described above.

One of the functions of the felt or blanket is, of course, to absorb and pass on the moisture evaporated from the underlying fabric, and for this reason it has always been considered essential that the felt or blanket be highly absorbent proposed, but my proposal so to treatmechanical fabrics, which have generally been understood to function in part, at least, as blotters, in order to improve their blotting" action and tgrfacilirate the passage of moisture therethrough is quite radical and believed to be entirely novel.

In general, a sanforizing blanket begins to I Percent moisture I thecloth being. treated comb ne to make, re s: face fibers brittle'so that they grad'u'al ,break'oif thus making the blanket thinner; "sometimsthifs wearcauses the blanket to become so thin as to destroy its shrinking function or ven' to pull apart; v T 1 i" While excessive dry 'eat alonewill in ure a woolen blanket, heat and moisture 'combine'dare much more damaging., ,,Because .of'this, many mills have .prolonged blanket'life' by increa ing the steam pressu're, at lea t on the vblank n'i'g cylinder, so that the blahktiuns'dryjer a ugh hotter. Otherv mills have, prolongedthe blanket life by merely'running' it. at a: slower rate "so that again the blanket runs drier but 'hott When the moisture. is driven fr that is being treated it passes to t I, where somev of it condenses, and some: passes through as vapor. Both of these things are always happening. at the, same time, andltlie ferrtent of each is determined.largelyby'the' quantity of water to beevaporated as well asthe', moisture content and temperature of the blanket;v j My experimentsfhave definitely indicated that a dry blanket is much more porous, than one which is wet. This difference in porosity is'ver'y marked as will be apparent from a comparison of the following porosity indices in whichalarger number indicates acl oser fabricf moisture content of the blanket increases its porosity to the passage of' air and water vapor is greatly reduced.

My investigations have also shown that jvwhen a'blanket has been treated to make it water repellent its porosity is greater than a" similar but untreated blanket which. ,containsjthe' same amount of .moisture. Forexamplef, two blankets both containing '70%of water hadiporositydndices of a1 and l09 for the treated ariduntreated blankets, respectivelmand with al9o moisture content the same blankets had relative 'porosities of and11'4. 1 I j i.

While itwould seem that.thellogicalj'wayto improve these felts or blankets would be 'to' make them absorbent so that they would more quickly absorb the water from the fabric that is being dried; actual. experiments indicate that by maki'ng the fabric water repellent the blanket remains: more opentothepassage of. air and water vapor; The moisture vapor condensed in the treated blanket. onits passage therethrough seems. to-accumu1ate on the surface of the fibers instead of being. absorbed" by them. Both-.01! these conditions-.facilitatethe dissipation of water and, as: a. result, the blanket runs eifectively drier and therefore; is less; injured by thezheat and moisv.

may conveniently'be used to increase the porosityJof. a. mechanical? fabric.

.After the felt or; blanket has received its final wash; it preferably is, prepared for further treat-- ment by making; it slightly acid. This may be dnne'rbymixing about. I lb. of commercial acetic acid; per litfifl lbs... of fabric with "a small quantity or. water inthe bottom of; the washer, running the fabric. in this solution for about 5 minutes and giving: it: a brieffrinse. This is done because many of the'water repellent materials are more stable in. a'very slightly acid solution. emulsified? solution; of. metal soap and wax such" forrexample,v as. Aridex is employed, which contains about 20% of solid material, about 11 /2 lbszofithe soap-waxcomposition' ma'y be used per Hill-lbs; of fabric- 1'I7he; water repellent material fibers substantially free of water-proofing or water-repellent material so that air and water vapor may pass freely therethrough.

'Ifherefore, by the term mechanical fabric" as used above and in the'appended claims I mean to include only those fabrics which are used in the mechanical arts and which must be pervious rather than impervious to hot water and hot water vapor. My invention is not concerned with waterproofing fabrics in the sense in which that term is ordinarilyunderstood and no claim is made to fabrics, or to the treatment of fabrics for use inzwearingapparel or in any other field where imperviousness to water is a desirable characteristic.

WhatIclaimls: a

1. The method or prolonging the life and in creasing the porosity to the passage of water and water vapor of a mechanical fabric which in normal use is subjected to comparatively high temperatures in the presence of moisture which comprises treating the fabric by immersion in a liquid which, when dry,will forma water-insoluble and water-repellent coating on the fibers of said fabric, subjecting said fabric to a centrifuging action while saturated with said liquid to remove the excess thereof from the interstices of said fabric about and between said fibers; and

' thereafter dryingsaid fabric.

2. The method of prolonging the life-and in- I creasing the porosity to-the'passage of water and water vapor of a mechanical fabric which in normal use is subjected to comparatively high temperatures in the presence of moisture which comprises treating the fabric by immersion in an emulsion of a metal soap and wax'to effect a coating of the fibers of said fabric therewith,

' subjecting said fabric, while saturated with said is mixed jwithpnly enough wat er in the washer I tosaturatethe fabric thoroughlyand uniformly.

that: a: final solution containing from about: /2:% to- 2%v of solidsv is quite effective. Solutionscontaininglarger quantities. of solids may be: usedf.-but;.since. 1ittle or no extra protectiiorr. is: given. their use isnot; recommended; for economicreasons. Furthermore, I prefert'o use solutionscontaining: solids in percentagesfof about: the above. order because it is possible, if the percentage: of solids is substantially increased, to reduce; instead of, increase. the effective: porosity of the fabric? by filling it with solid material. Afterrunning'in thissolution'for'from. v

5410.1;0mifiutestheiabrim may be taken out without. any rinsa. extracted; driedlandi finished by the. usual processes. l

After the blanket: has beenv extracted in a centrifnge, itusually contains about one-half of its own. weight. in water. Thus, if ther is-2% of solids. in. the: treating, solution there will be about 1i%' of solidsintheifinishedifabric.

Thetimeofi running. the blanket in the solutibns: is f not: critical and it is: only necessary that the: fabric be thoroughly and" uniformly soaked. As distinguished: from the treatment of fabrics with metal soaps and waxes in order to make them: waterproof',, it should bornev in mind. that my treatment; contemplates: impregnating or coating the individual fibers only while maintaining; the interstices; of the; fabrics about the g emulsion, to'a centrifuging action to removethe excess of said emulsion from the interstices of,

said fabric about and'betweensaid fibers, and thereafter drying said fabric.

'3; The method of prolonging the life and increasing the porosity to the passage of water and water vapor of a mechanical fabric which in normal use is subjected to comparativelyhigh temperaturesin the presence of moisture which comprises saturating said fabric with watercoutaining a metal soap, removing from said fabric about one half of the water absorbed thereby before any substantial evaporation thereof has taken place, and thereafter drying. said fabric by evaporating the balance of the water therein, whereby to deposit a water-repellent coating on the fibers thereof.

4. The method of prolonging the'life and increasing the porosity to the passage of ,water and water vapor of a mechanical fabric which in normal use is subjected to comparatively high temperatures in the presence of moisture which comprises saturating'said fabric with water containing a metal soap' and an organic wax, re-

.moving from said fabric about one-half of the saturating liquid before any substantial evaporation thereof has taken place, and thereafter drying said fabric by evaporation of the moisture therein to effect the deposit on the fibers thereof of a water-repelent coating of insoluble soap and wax.. v

' CARLTON C; GORDON. 

